1. Field of the Invention
The present invention relates to a thin buzzer and, more particularly, to the improvement in a small and thin buzzer which is directly mounted on a printed circuit board.
2. Description of the Related Art
Various electronic parts are standardized as chip parts in order to enable automatic assembly. A thin buzzer which is directly mounted on a printed circuit board so as to be used as a call buzzer for a pocket receiver such as a pager has also been developed as a buzzer which can be mounted on a printed circuit board by applying a cream solder or the like to the buzzer in the same way as in mounting such chip parts.
Japanese Patent Laid-Open No. Hei 2-34900 (Japanese Patent Application No. Sho 63-185061) discloses an example of such a buzzer equipped with terminals for mounting the buzzer on a printed circuit board. These terminals provided on the base of the buzzer enable the buzzer to be automatically mounted on a printed circuit board.
Such a buzzer can be mounted on the desired printed circuit board on a series of automatic assembly lines in the same way as other electronic chip parts, and the application range for a buzzer is greatly enlarged.
A conventional buzzer, however, cannot be made thin and since the thickness of the buzzer is larger than the other electronic chip parts, the size of an apparatus incorporating such a printed circuit board cannot be made small. Japanese Utility Model Laid-Open No. Sho 63-33197 discloses a small-sized and light-weight buzzer which is used for a wireless receiver. In this conventional apparatus, however, the structure for connecting the terminals for external connection and the exciting coil terminals is apt to increase the thickness of the buzzer, so that it is impossible to produce a thin buzzer which fits the demands.
To state this more specifically, in the conventional treatment of exciting coil terminals, the coil terminals guided through an opening portion are soldered to the terminals for external connection and the opening portion is thereafter sealed by a sealing adhesive. In this case, the solder or the sealing adhesive sometimes protrudes out of the buzzer case depending upon the unevenness of the amount of solder or sealing adhesive. As a result, in mounting the buzzer on the circuit board, the buzzer as a whole protrudes from the circuit board so that positioning of the buzzer on the circuit board by a mounting machine is made difficult.
As conventional general buzzers, for example, those having the structures shown in Japanese Utility Model Laid-Open Nos. Sho 54-178522, Sho 57-105700 and Sho 57-153398 are known. In this conventional buzzers, the exciting coil terminals are treated in the buzzer assembly. Since the terminals for external connection are close to the coil terminals, the workability is very bad when treating the coil terminals. Furthermore, since these buzzers have a general buzzer structure, they cannot be mounted on a printed circuit board unlike a buzzer in accordance with the present invention.